1. Field of the Invention
This invention relates to a new and improved method and apparatus for making an expandable gusset envelope, such as a file pocket. In particular, it relates to an improved method and apparatus for forming a folded corner portion in an accordion fluted or pleated gusset member for use in constructing such an envelope.
2. Description of the Prior Art
Expandable gusset envelopes and methods for fabricating such envelopes are well known. An example of an expandable gusset envelope is shown in U.S. Pat. No. 1,968,165 which issued on July 1, 1934. The expandable capability of such envelopes is derived from the accordion fluted or pleated structure which the gusset member possesses. Previous methods for fabricating such envelopes have the limitation that the fold of the corner portion must be made by hand, a method that is time consuming and wasteful of labor resources. In forming a corner portion by hand, the pleated or fluted gusset member is first provided with a score extending transversely to the length of the gusset member. A human operator then must form by hand V-shaped notches extending away from the score line adjacent the corner portion. Due to the fluted construction, a gusset member cannot be folded at a corner portion until the operator forms a notch between each flute adjacent the score line. The notches can be formed on either the side portion or the bottom portion of the gusset member, but preferably at the bottom portion. Not only is the manual forming of the notches at each of the two corner portions tedious and time consuming.